Staphylococcus aureus dry stress survivors have a heritable fitness advantage in subsequent dry exposure

Staphylococcus aureus is a major cause of hospital-acquired infections. The ability to survive on abiotic surfaces is an important characteristic that facilitates transmission between human hosts. We found that S. aureus survivors of dry surface incubation are resistant to subsequent dry stress exposure. Survivors also had reduced sensitivity to the disinfectant chlorhexidine gluconate, but not to ethanol. By using a set of mutants in cardiolipin synthase genes, we further demonstrated that the housekeeping cardiolipin synthase, Cls2, was significant for survival on dry surface. Taken together, this study provides insights into S. aureus survival outside of a host.     

Growth performance,haematological assessment and chemical composition of Nile tilapia,Oreochromis niloticus (Linnaeus, 1758) fed different levels of Aloe vera extract as feed additives in a closed aquaculture system

A 105-day experimental trial was conducted to assess different levels of dietary Aleo vera extract supplementation on water quality parameters, proximate composition, growth performance and haematological parameters of fry Oreochromis niloticus. Four different percentages of dietary leaf extract powder of Aleo vera (ALE) with a basal feed, designated as, i.e., T0 (Control group; without ALE), T1 (1% ALE), T2 (2% ALE), and T3 (3% ALE). Fish fry was reared in concrete tanks (7.0 m, 1.6 m, 1.0: L, W, H; water volume 11.2 m3/tank), with an average initial weight 4.04 ± 0.03 g/ fry, and each treatment was triplicated. Fry was randomly distributed at a stocking rate of 450 individuals/ tanks. The water quality parameters revealed that temperature, pH, salinity, dissolved oxygen (DO) and nitrates were found in a promising range as given by FAO/WHO limits. However, the record values obtained for Electric Conductivity (EC), Total dissolved solids (TDS), and alkalinities were not found in all tanks' suitable range according to FAO/WHO limits. The results revealed a significant impact of different percentages of dietary ALE supplementation on fry's body composition and haematological parameters. Moreover, the final body weight, final body length, average daily weight gain (g), net weight gain (g) and specific growth rate (%) were significantly higher (p < 0.05) in T1 and T2 compared with T0 and T3 treatments. The poorest feed conversion ratio was recorded in the T2 group compared with other treatments. Thus, the current study provides information about the nutritional quality of Nile tilapia culturing in Pakistan.     

AGFA Drystar 5500干式相机图像质量控制

在医院集中式DICOM医用打印系统中,一台高速DICOM打印机往往连接着多台DICOM主机。由于各主机对输出图像的质量要求不同,如何在打印机端适应主机的要求,控制打印图像质量,是得到令人满意的胶片输出的医用图像的关键。本文以AGFADrystar5500干式相机为例探讨该DICOM医用打印机的图像控制原理和方法,以及在临床上的实际应用。     

Comparison of Rapid DNA Extraction Methods Applied to PCR Identification of Medicinal Mushroom Ganoderma spp.

Abstract

Four different DNA extraction methods were used to extract genomic DNA of the medicinal mushroom Lingzhi from its developing stage materials, such as mycelium, dry fruiting body, or sliced and spore powder or sporoderm‐broken spore powder. The DNA samples were analyzed using agarose gel electrophoresis, UV spectrophotometer, and PCR amplification. According to the average yields and purity of DNA, high salt concentrations and low pH methods were the best for DNA extraction. The mycelia and sporoderm‐broken spore powder yielded higher and purer DNA. The method developed could effectively eliminate the influence of the secondary metabolites to DNA extraction. The DNA samples extracted from the developed method could be successfully used for PCR applications.     

Driving factors of a vegetation shift from Scots pine to pubescent oak in dry Alpine forests

An increasing number of studies have reported on forest declines and vegetation shifts triggered by drought. In the Swiss Rhone valley (Valais), one of the driest inner‐Alpine regions, the species composition in low elevation forests is changing: The sub‐boreal Scots pine (Pinus sylvestris L.) dominating the dry forests is showing high mortality rates. Concurrently the sub‐Mediterranean pubescent oak (Quercus pubescens Willd.) has locally increased in abundance. However, it remains unclear whether this local change in species composition is part of a larger‐scale vegetation shift. To study variability in mortality and regeneration in these dry forests we analysed data from the Swiss national forest inventory (NFI) on a regular grid between 1983 and 2003, and combined it with annual mortality data from a monitoring site. Pine mortality was found to be highest at low elevation (below 1000 m a.s.l.). Annual variation in pine mortality was correlated with a drought index computed for the summer months prior to observed tree death. A generalized linear mixed‐effects model indicated for the NFI data increased pine mortality on dryer sites with high stand competition, particularly for small‐diameter trees. Pine regeneration was low in comparison to its occurrence in the overstorey, whereas oak regeneration was comparably abundant. Although both species regenerated well at dry sites, pine regeneration was favoured at cooler sites at higher altitude and oak regeneration was more frequent at warmer sites, indicating a higher adaptation potential of oaks under future warming. Our results thus suggest that an extended shift in species composition is actually occurring in the pine forests in the Valais. The main driving factors are found to be climatic variability, particularly drought, and variability in stand structure and topography. Thus, pine forests at low elevations are developing into oak forests with unknown consequences for these ecosystems and their goods and services.     

The responses of Apis mellifera jemenitica to different artificial queen rearing techniques

In the current study, we investigated if any variations exist in acceptance rate of grafted larvae and quality of queens reared in different queen cell cup sizes, between wet and dry grafting and between queen right and queen less conditions of A. m. jemenitica colonies. The acceptance rate of grafted larvae in different queen cell cup sizes (7.0 mm, 7.5 mm, 8.0 mm, 8.5 mm) were varying from 69 to 71% and the variations were not significant among the different queen cups sizes but averagely lower than the acceptances recorded for other races. Out of the 172 dry grafted larvae, only 56.4% of them were accepted while in wet grafting out of 174 grafted larvae 77.01% were accepted. Regarding the rate of sealing, 48.84% and 71.84% of them sealed for dry and wet grafts, respectively. The observed variation in the rate of acceptance and sealing were significant (N = 346, df = 1, P < 0.0001) between the two techniques. However, there was no significant difference in fresh weight of emerged queens between the two grafting methods. Out of the 324 grafted larvae given to queen right and queen less starter colonies each; 106 (32.72%) and 252 (73.68%) were accepted in queen right and queen less starter colonies, respectively and the variation was highly significant at P < 0.0001. The total number of sealed pupae were 82 (25.31%) and 216 (63.16%) for queen right and queen less colonies, respectively and the variations was significant at P < 0.0001. From the study it can be concluded that A. m. jemenitica colonies can rear significantly more queens under wet grafting and in queen less colonies conditions than dry grafting and queen right conditions     

Environmental controls on bacteriohopanepolyol profiles of benthic microbial mats from Lake Fryxell,Antarctica

Bacteriohopanepolyols (BHPs) are pentacyclic triterpenoid lipids that contribute to the structural integrity and physiology of some bacteria. Because some BHPs originate from specific classes of bacteria, BHPs have potential as taxonomically and environmentally diagnostic biomarkers. For example, a stereoisomer of bacteriohopanetetrol (informally BHT II) has been associated with anaerobic ammonium oxidation (anammox) bacteria and suboxic to anoxic marine environments where anammox is active. As a result, the detection of BHT II in the sedimentary record and fluctuations in the relative abundance of BHT II may inform reconstructions of nitrogen cycling and ocean redox changes through the geological record. However, there are uncertainties concerning the sources of BHT II and whether or not BHT II is produced in abundance in non‐marine environments, both of which are pertinent to interpretations of BHT II signatures in sediments. To address these questions, we investigate the BHP composition of benthic microbial mats from Lake Fryxell, Antarctica. Lake Fryxell is a perennially ice‐covered lake with a sharp oxycline in a density‐stabilized water column. We describe the diversity and abundance of BHPs in benthic microbial mats across a transect from oxic to anoxic conditions. Generally, BHP abundances and diversity vary with the morphologies of microbial mats, which were previously shown to reflect local environmental conditions, such as irradiance and oxygen and sulfide concentrations. BHT II was identified in mats that exist within oxic to anoxic portions of the lake. However, anammox bacteria have yet to be identified in Lake Fryxell. We examine our results in the context of BHPs as biomarkers in modern and ancient environments.     

Identification key for European strand-forming house-rot fungi

An identification key for 20 common strand-forming indoor wood decay fungi is given. The key is based on observations of material from affected buildings and on wood samples that have been incubated in the laboratory. The key is with macro- and microscopic photographs.